Outer peripheral faces of insulated wires which are connected to electronic devices mounted to an automobile to supply electric power and send and receive signals may be surrounded and protected by protective members in some cases as necessary in order to prevent damage caused by interference with surrounding parts and entry of water.
As the protective members for surrounding the insulated wires, there are an accordion corrugated tube for preventing interference of the insulated wire with the surrounding parts, the grommet for preventing entry of water, and the like, for example, and the protective members have different effects.
The protective members may be used separately or in combination with each other as described in Patent Document 1, for example, in which a grommet is used in combination with a corrugated tube.
In the grommet described in Patent Document 1, a plurality of corrugated tube-side sealing ribs, each of which protrudes from an entire circumference, are arranged along an axial direction on an inner peripheral face of a corrugated tube-side end portion of the grommet in which a corrugated tube is fitted and a mounting groove (hereinafter referred to as “fastening fixing portion”) into which a fastening band (hereinafter referred to as “fastening member”) is fastened is provided to an outer peripheral face of the grommet corresponding to the corrugated tube-side sealing ribs.
The corrugated tube-side sealing ribs are provided with the same pitch as peaks and troughs forming an accordion shape of the corrugated tube which is fitted in the grommet. In other words, the corrugated tube-side sealing ribs are arranged at equal intervals as shown in FIG. 2 in Patent Document 1.
The above-described grommet is assumed to be able to reliably block water by fitting the corrugated tube-side sealing ribs and the troughs of the corrugated tube with each other by use of protruding and recessed shapes and integrally fastening an outer peripheral face of the fitted portion by use of the fastening member.
However, because section stiffness of the corrugated tube-side end portion of the grommet described in Patent Document 1 is increased by the corrugated tube-side sealing ribs disposed at the equal intervals. In other words, shape retaining performance of the corrugated tube-side end portion increases and therefore an influence of deformation by fastening of the fastening member reaches the end portion to deform the portion. In other words, the end portion is deformed as a result of the deformation of the fastening fixing portion and a clearance is created between the corrugated tube and the grommet, which may result in reduction in water-blocking performance.